Fuel injectors operate to inject controlled amounts of fuel into a combustion chamber of an internal combustion engine. Typical fuel injectors include a body or housing containing one or more actuators arranged to operate valves that route fuel at a high pressure out of the injector and into the engine. More specifically, a typical injector housing forms a needle chamber positioned at a distal end of the injector and terminates at a “nozzle.” For direct injection engines, the nozzle generally projects at least partially into the combustion chamber of the engine. The nozzle forms a plurality of nozzle openings configured for injecting or spraying pressurized fuel from the needle chamber into the combustion chamber.
Flow of fuel through the nozzle openings is controlled with a needle or check valve positioned for reciprocating movement within the needle chamber. A typical needle valve can be selectively actuated to supply fuel from the needle chamber at desired times and for desired durations. The timing of injection events or needle valve actuations may depend on factors such as the operating speed of the engine. The duration of each injection often depends, at least in part, on the amount of fuel desired per combustion stroke of the engine or, stated differently, on the power output of the engine.
With more stringent emissions and fuel consumption requirements, fuel injectors are required to operate at higher injection pressures and with greater precision.